Cellular telephones offer many advantages; the greatest of which is mobility. A cellular telephone user can communicate with other persons and devices while on the go, and in most geographic locations.
The mobility advantage is even greater when the cellular telephone user travels out of his or her home location. When the cellular telephone user leaves a home network, he or she can roam in other cellular telephone networks. Optimally, the only discernible difference is the billed cost of roaming communications.
However, a difficulty in obtaining service can occur when roaming. This is especially true when the cellular telephone user is roaming in another country, geographic region, or continent. Such long-distance roaming can lead to difficulties in establish communications when the user has to get service access to a wireless network having different protocols, different service type, and different service providers.